Purpose: The purpose of the present study was to model the relationship between negative and positive work-family spillover with work engagement and happiness with the mediating role of perceived stress in Isfahan city employees.

Method: This research was cross-sectional and descriptive, employing structural equation modeling. The population of this research was the employees of Isfahan city (1,589,044 individuals). A sample of 279 people was selected using convenience sampling, following Bentler and Chu's formula (1987) to determine the appropriate sample size for structural equation modeling research. To collect data, the Grzywacz and Marks Positive and Negative Work-Family Spillover Scale (2000), the Wartig, Forshaw, South, and White Perceived Stress Scale (2013), the Hills and Argyle Oxford Happiness Inventory (2002), and the Schaufeli, Bakker, and Salanova Utrecht Work Engagement Scale (2006) were used. The data were analyzed using SPSS and AMOS software version 24.

Findings: The findings of the research showed that perceived stress fully mediates the relationship between negative work-family spillover and work engagement, and a partial mediating role in the relationship with happiness. The direct relationship between negative spillover and happiness was also significant (β=-0.17 and p<0.01). Positive work-family spillover was significantly related to both work engagement (β=0.31, p<0.01) and happiness (β=+0.35, p<0.01), and perceived stress did not play a mediating role in these relationships. The final research model had a good fit with the data (RMSEA=0.075 and p<0.01) and explained 28% of the variance of work engagement and 20% of the variance of happiness.